Mission Type: Orbiter
Launch Vehicle: Titan IIIE-Centaur (TC-5 / Titan no. E-5 / Centaur D-IT)
Launch Site: Cape Canaveral, USA, launch complex 41
Spacecraft Mass: 370 kg
Spacecraft Instruments: 1) plasma detector; 2) two flux gate magnetometers; 3) search-coil magnetometer; 4) plasma and radio wave experiment; 5) cosmic-ray detectors; 6) electron detectors; 7) zodiacal light photometer; 8) micrometeoroid analyzer; 9) celestial mechanics experiment; 10) Faraday rotation experiment and 11) occultation experiment
Deep Space Chronicle: A Chronology of Deep Space and Planetary Probes 1958-2000, Monographs in Aerospace History No. 24, by Asif A. Siddiqi
National Space Science Data Center, http://nssdc.gsfc.nasa.gov/
Helios 2 was the second spacecraft launched to investigate solar processes as part of a cooperative project between the Federal Republic of Germany and the United States, in which the former provided the spacecraft and the latter the launch vehicle.
Like its twin, the spacecraft was put into heliocentric orbit. In contrast to Helios 1, however, Helios 2 flew three million kilometers closer to the Sun, achieving perihelion on 17 April 1976 at a distance of 0.29 AU (or 43.432 million kilometers). As a result, the spacecraft was exposed to 10 percent more heat than was its predecessor.
The spacecraft provided important information on solar plasma, the solar wind, cosmic rays, and cosmic dust, and also performed magnetic field and electrical field experiments.